In recent years, microRNAs (miRs) have emerged as an important novel class of regulatory RNA, which have a profound impact on a wide array of biological processes. These small (typically 18-24 nucleotides long) non-coding RNA molecules can modulate protein expression patterns by promoting RNA degradation, inhibiting mRNA translation, and also affecting gene transcription. miRs play pivotal roles in diverse processes such as development and differentiation, control of cell proliferation, stress response and metabolism. The expression of many miRs was found to be altered in numerous types of human cancer, and in some cases strong evidence has been put forward in support of the conjecture that such alterations may play a causative role in tumor progression. There are currently about 700 known human miRs, and their number probably exceeds 800.
Classification of cancer has typically relied on the grouping of tumors based on histology, cytogenetics, immunohistochemistry, and known biological behavior. The pathologic diagnosis used to classify the tumor taken together with the stage of the cancer is then used to predict prognosis and direct therapy. However, current methods of cancer classification and staging are not completely reliable.
The treatment of bladder carcinoma is dictated by several factors. The most clinically significant prognostic parameters for tumor recurrence and invasion of bladder cancer are grade, stage, lymphatic invasion, tumor size, carcinoma in situ, multifocality and the rate of tumor recurrence. Of these parameters, pathological stage and tumor grade are seen as most important. However, staging errors are possible. Under-staging occurs in cases of high and intermediate stage disease, of which approximately 33% are typically under-staged and 10% are typically over-staged, respectively. An ideal prognostic factor must be reliable to direct treatment decisions in individuals.
Cytological analysis of voided urine is the most commonly used non-invasive method for detecting transitional cell carcinoma, but its utility is severely constrained by its low sensitivity. Several potential diagnostic markers for bladder cancer have been identified, including nuclear matrix protein 22, bladder tumor antigen, and telomerase. Although these markers are more sensitive than urine cytology for detecting bladder cancer, their use is limited by low specificity. Specific genetic alterations have been implicated in the molecular pathogenesis of transitional cell carcinoma, with mutations reported in cell cycle regulatory genes, oncogenes, and tumor suppressor genes. However, it has proven difficult to use these genetic alterations as diagnostic markers of bladder cancer because of their low sensitivity.
Procedures used for detecting, diagnosing, monitoring, staging, and prognosticating cancer of the small intestine are of critical importance to the outcome of the patient. Patients diagnosed with early stage cancer generally have a much greater survival rate as compared to the survival rate for patients diagnosed with distant metastasized cancers. New diagnostic methods which are more sensitive and specific for detecting cancer of the small intestine are clearly needed.
Nearly any primary tumor site can deposit metastases in the liver, since the liver filters blood from throughout the body. Most discussions related to the treatment of metastatic tumors in the liver focus on those originating from the colon. In fact, the most common cause of death from colorectal cancer is liver metastasis.
Up to 50% of liver metastases are of colorectal cancer origin, while the remainder metastasizes from a wide variety of primary cancer sites including sarcomas, breast and kidney, as well as neuroendocrine tumors.
Hepatocellular carcimoma (HCC—the liver primary tumor) may be solitary or multicentric, and it may mimic liver metastases. Furthermore hemangiomas and liver metastases are often confused in imaging methods. In general, the imaging appearances of liver metastases are nonspecific, and biopsy specimens are required for histological diagnosis. Various biochemical markers have been proposed to indicate liver metastases. However, the diagnostic accuracy of tumor markers has not yet been defined.
Therefore, there is a need for a more efficient and effective method for diagnosing specific types of cancers.